Virologist Broccoli: "Viral load of the virus high, that is, there is new active infection"

2020-10-22T18:09:58.819Z

The viral load is rising to high levels, that is the number of copies of the genetic material of the new coronavirus present in a milliliter of biological material taken with the swab, so much so that "in 80% of positive cases it is now over one million", declared virologist Francesco Broccolo, from the University of Milan Bicocca and director of the Cerba laboratory in Milan. "Very often - he added - the viral load is even higher, up to billions in asymptomatic or symptomatic subjects between 30 and 60 years of age". The data indicates that the infections are recent: "A very high viral load - Broccolo noted - is an indication of a new active infection". That is, it indicates that "the infection is recent and primary, that is, it has not persisted for months". Classic molecular swabs and rapid tests According to Broccolo, rapid molecular tests for the diagnosis of the new coronavirus are useful in this moment of emergency, in which the capacity of laboratories to make swabs is reaching the maximum threshold of 200 thousand, but it would be a mistake to count them with the traditional ones in the epidemiological analysis and it should be kept in mind that "they cannot give a guarantee of negativity or viral clearance in subjects in isolation," Broccolo noted. "We started in March with 30,000 swabs per day in Italy and the maximum was reached with 177,000 in a single day for the classic molecular swab. It was hard to exceed 150,000 and now it gets up slowly", he continued. Broccoli. The important thing, he added, "is not to mix data from traditional molecular swabs with rapid antigenic swabs: this would undermine statistics and epidemiological predictions as rapid antigenic tests only detect positives with a high viral load." For this reason, he added, "rapid antigenic swabs cannot give a guarantee of negativity". However, they are necessary at this stage, as the international scientific community has recently acknowledged, the virologist said referring to an article recently published in the New England Journal of Medicine: "In a pandemic context in which there is a desperate need to make swabs to track cases. This is a worldwide problem. " The choice, he continued, was to justify the use of the rapid antigen test to identify subjects with high viral load. However, it should not be forgotten that "it is a test about a thousand times less sensitive than the molecular test and this has raised the discussion in the scientific world as to whether it is ethical or not to use it, but it was decided to do so in light of the 'desperate need' to identify cases. In light of this situation, the rapid test increases the firepower of the ability to swab, as long as he is not given a license of negativity. "